This project is concerned with the thorough identification and characterization of transport ATPases in the corneal endothelium that may be directly or indirectly related to deturgescence. It is directed toward revealing some of the biochemical nature of the dehydration pumps (i.e., deturgescence) and factors that may control the pumps under normal, stressed and therapeutic conditions. Sodium-potassium stimulated ATPase and non-specific magnesium stimulated ATPase will be further characterized in the plasma membranes of bovine corneal endothelial cells. Anion-stimulated ATPase will be further characterized in the mitochrondria of bovine corneal endothelial cells. Agents known to stimulte or suspected to stimulate deturgescence will be used to test alterations in the activities of these enzymes. Agents used for pharmacological intervention of ocular function will be tested for their possible inhibitory effects on the activities of these enzymes. The activities of the ATPase found in the plasma membranes and mitochondria of corneal endothelial tissue cultures will be compared with the activities found in fresh tissue. Assays will be run by the measurement of inorganic phosphate released from the enzymatic hydrolysis of ATP and compared to tissue protein levels.